1. Field
The described technology relates generally to a rechargeable battery assembled by vacuum sealing.
2. Description of the Related Art
A rechargeable battery differs from a primary battery in that it can be repeatedly charged and discharged, while the latter can only irreversibly convert chemical energy to electrical energy. A small sized rechargeable battery is used as a power supply for small electronic devices such as cellular phones, notebook computers, and camcorders, while a medium or large sized rechargeable battery is used as a power supply for driving motors in hybrid vehicles and electric vehicles.
Typically, a rechargeable battery includes an electrode assembly performing charging and discharging, a case receiving the electrode assembly, a cap plate coupled to an opening of the case, and an electrode terminal drawing the electrode assembly out to an outer side of the cap plate.
The rechargeable battery is assembled by being connected to the electrode assembly through the electrode terminal, installing the cap plate, inserting the electrode assembly into the case, and then welding the cap plate to the case.
After that, an inner space of the rechargeable battery is set to be vacuumed through an electrolyte injection opening formed in the cap plate during which a center portion of a wide side wall of the case may be deformed to be more concave compared to outer edge portions thereof.
Thus, the wide side wall of the case presses the electrode assembly and specifically, the center portion of the wide side wall may be subject to greater pressure compared to the outer edge portions. In other words, the electrode assembly may be non-uniformly pressed with respect to the side wall so that the electrode assembly may be prevented from uniformly charging and discharging depending on a location corresponding to the wide side wall of the case.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.